What to eat before a marathon: Fueling without the overwhelm

So here you are, in those final days before a marathon, caught between excitement and nerves.

“Okay, I’ve made it through weeks of marathon training…now I just need to nail the nutrition.” 😅

But then the questions start popping up:

➡️ Should I carbo-load? 🤔 How much?
➡️ What about protein?
➡️ What do I eat on race morning?
➡️ What if I hit the wall?

You’ve heard all kinds of advice, but what’s actually going to work for you?

The countdown is on, and you’re laser-focused: crossing that finish line strong.

You want energy that lasts, no stomach issues, and zero regrets about what you ate (or didn’t eat).

Sound familiar? You’re not alone.

What to eat before a marathon can feel overwhelming…but don’t worry, I’ve got you.

Let’s talk about it: what to eat, drink, and avoid in the days before your marathon.

Because with the right fuel, you’ll have the energy to push through (even that wall!) when it counts.

📝 Quick note! I’m sharing what I’ve learned from reputable sources and from my own experience as a marathon runner. But this isn’t medical or nutrition advice. Definitely check in with a healthcare pro for guidance that’s right for you.

Carb-Loading: Practice Makes Perfect

Carb-loading isn’t just an excuse to eat pasta (or bread! Rice! Noodles!) for every meal. 🍝

You’re also giving your muscles extra fuel to stash away as glycogen (that’s your body’s main energy source for endurance).

This stored glycogen? It kicks in so you have energy when the miles get long. (Mueller et al., n.d.)

⚙️ How it works

Carbs *waves wand* 🎩 ➡️ glycogen: When you eat carbs, your body transforms them into glucose. And that gets squirreled away as glycogen in your muscles and liver.

This is the magic fuel…your body’s own energy gel… that your muscles rely on during long runs. (p.s. I’ve got even more tips on what to eat on long runs (so you don’t crash at mile 6).
More glycogen = more staying power. You’re basically stashing fuel in your legs like snacks in your race belt. (Sedlock, 2008)
You can’t cram for it! And no, this isn’t a night-before-the-race kind of thing. You build it up gradually during the days leading in.⚡️
That means you’ll need to taper off your running for 2-3 days + eat about 8-12g of carbs per kg of body weight daily.

📌 Wait…what about fat? Isn’t that fuel too? The TL;DR on fat vs. carbs

Yep! Your body can use fat for energy, especially during slower runs.

But when the pace picks up or you’re pushing through mile 20? Carbs are the MVPs. Quick, efficient, and your muscles love ’em.

✅ Practice makes perfect

Test out carb loading (an extra piece of toast, a little more noodles than usual) so you can figure out what feels good.
Note the foods that make you feel a little too full or sluggish. So…how did you feel? Energized and ready to keep going? Or did you hit a wall?
Did you feel bloated or sluggish?
Was it smooth sailing or did you feel off?
What would you need to tweak the next time?

2 – 3 days before your marathon: Your carb-loading game plan

⏰ Timing matters

Start 2-3 days pre-race while reducing the volume of your runs.
Eat about 8-12g of carbs per kg of body weight daily. Extra rice, a handful of dried fruit, and an energy drink can boost your carbs without making you feel too bloated.
Skip the big meals before bed if you want to avoid tossing and turning all night.

🍚 What to eat

Go for easy-to-digest carbs like white rice, noodles, sweet potatoes, oatmeal, bananas, and steamed buns.
Keep high-fiber stuff (like beans and raw veggies) to a minimum so your stomach stays happy.

⚖️ How much

Slowly add carbs to your meals (like tossing in an extra serving of rice at lunch or grabbing a bagel for a snack).
But don’t go overboard! Aim to feel fueled, not stuffed. A little extra water weight (like 2-4 lbs) is totally normal because glycogen holds onto water.

Hydration for marathoners: Don’t wait until you’re thirsty! (Covertino et al, 1996)

That’s actually your body’s way of saying, “Hey, I’m already behind!”

Being dehydrated can mess with your performance. If you stay on top of hydration, you’ll feel less fatigued, fewer cramps, and have more energy.

Hydration isn’t something you can leave to chance on race day.

📌 Practice makes perfect. Use your long training runs to dial in your hydration strategy so that on race day, your body knows exactly what to expect.

How to practice your hydration strategy

Before your long run: Start hydration early!

⏰ 4 hours before

✅ Drink 16-24 oz of water with electrolytes (think: sports drinks or electrolyte tablets).
➡️ Why? It helps your body hold onto fluids, so you’re not starting behind the hydration game.

⏰ 2 hours before

✅ Drink 8-16 oz of an electrolyte drink to top off your hydration without overloading your stomach.
➡️ Why this range? It’ll prevent any stomach sloshing and mid-run bathroom stops.

During your long run: Keep sipping!

⏰Every 15-20 minutes

💧Sip on 4-8 oz of fluid with 200-300 mg of sodium (adjust this based on how much you sweat and how hot it is). That’s about one electrolyte tablet or a small pinch of salt stirred into your drink.
For heavy sweaters: If you’re a big sweater, you might need fluids of up to 32 oz/hour.

After your run

⏰ Within 30 minutes

🔄 Rehydrate with 16-24 oz of water and add 500-1,000 mg of sodium (hello, electrolyte tablets or salty snacks).

Why this practice matters

When you stick to the same hydration routine during your long runs, you’re teaching your body exactly what to expect on race day.

That way, there’s no surprises and less worries! Keep practicing and you’ll feel like you’ve got this down to a science.

Pre-marathon hydration quick tip checklist

Practice these during training to dial in your hydration strategy, so you’re all set when race day arrives.

📝 Hydration checklist

💧Look for that pale yellow shade (like lemonade). If it’s darker, time to drink more!
⚖️ Weigh yourself before and after a 1-hour run. For every pound lost, you need to drink 16 oz to replace it.
🧂 Don’t just drink plain water. Too much without electrolytes can cause a dangerous condition called hyponatremia.
⏱ Don’t wait to get thirsty! Keep sipping throughout the day.
🏃🏻‍♀️ Long run? Hot weather? Grab an electrolyte drink or tablets.
🧊 Keep fluids cool (59-72°F or 15-22°C) for to make it easier for your body to absorb and for you to drink.

⚠️ Hyponatremia heads up: If you drink too much plain water without balancing it with sodium, it can dilute your blood sodium levels, which can lead to hyponatremia. Keep those electrolytes in check!

The day before: keep it simple, keep it familiar

The day before your marathon, don’t stress about trying anything new and avoid anything that might mess with your stomach.

Keep it simple! High-carb, low-fiber.

Load up on carbs ~8-12g carbs per kg of body weight spread across meals (and snacks!) You don’t need to obsessively track every gram, but having a ballpark helps.

Some good carb-y snack options:

Dried fruit
Mochi with red bean paste
Roasted sweet potatoes
Baked potato with greek yogurt
Ginger molasses granola
Kimchi rice ball

And meal carb-y options

Chicken fried rice with veggies + eggs
Bison meatballs with marinara sauce
Shanghai cold noodles

Hydration: Don’t go overboard

You’ve been hydrating all week, so no need to chug a gallon of water before bed. Sip, don’t drown. You’ll thank me at 3 a.m. 🛌

Marathon race day: fuel up, but keep it light

🍽 Pre-race breakfast: keep it familiar

Aim for 2-3 hours before the race.
Go for something simple and carb-heavy like oatmeal with banana, milk bread with coconut jam, a bagel with peanut butter, or rice porridge.
You’re looking for about 50-100 grams of carbs, but don’t go overboard.
No time to get fancy or experiment with new foods today!

💧 Hydration: sip, don’t chug

A little water or a sports drink is perfect here.
Keep sipping, but don’t drown yourself. Hydration is key, but you want to feel ready, not waterlogged.
Drink about 16oz of an electrolyte drink 2 hours pre-race, then keep sipping 4-8oz every 20 minutes until the start.

⚠️ Heads up on hyponatremia: If you drink too much plain water without the sodium to balance it out, you can mess with your blood sodium levels.

This could lead to hyponatremia. So, skip the plain water and aim for 500-1,000mg of sodium per liter in your drink.

Keep those electrolytes in check!

You’ve got this: Let’s go 💨

The secret sauce to marathon nutrition? It’s not just what you eat—it’s having a plan that works for your body.

Those long runs? They weren’t just for building endurance.

They were your personal fuel-testing lab. So now? It’s go time.

✨ Stick with what works! No surprise snacks on race day

✨ Carbs = your go-to fuel

✨ Hydration matters (electrolytes too, not just plain water)

✨Your body’s smart…listen to it

You’ve put in the miles. You’ve tested the fuel.

Now trust it, roll with it, and soak it all in. You’re ready. 🏁